Means for securing knobs and dials to instrument shafts



Dec. 1, 1925.

H. J. KASCH MEANS FOR SECURING KNOBS AND DIALS TO INSTRUMENT SHAFTS Filed July 5. 1924 INVENTOR, QMVK,

ATTORNEY was ' Patented Dec. 1, 1925.

UNITED STATES! PATENT OFFICE.

HENRY J. RASGH, OF DAYTON, OHIO, ASSIGNOR TO THE KU'RZ-KASGI-I COMPANY, OF

SOUTH BROADWAY, NEAR DAYTON, OHIO, A CORPORATION OF OHIO.

MEANS FOR SEOURING KNOBS AND DIALS TO INSTRUMENT SHAFTS.

Application filed July 3,

To all whom it may concern:

Be it known that I, HENRY J. KASCH, a citizen of the United States, residing at Dayton, in the county of Montgomery and State of Ohio, have invented certain new and useful Improvements in Means for Securing Knobs and Dials to Instrument Shafts, of which the following is a specification.

This invention relates to new and useful improvements in means for securing knobs and dials to instrument shafts, and more particularly to means for securing a knob and a dial to a cylindrical shaft or spindle in radio apparatus.

' It is one of the principal objects of m invention to provide a loose member, su as a tapered bushin for firmly securing a knob and dial, or a ob, on an instrument shaft. In those cases where the knob and dial are made integral and secured in position on the shaft by set screws, the operation of the latter is difficult because of their inaccessible ositions. These set screws also give the device a rough appearance. I

My loose gripping member, which may take the form of a tapered split bushing, will not only close in tightly upon the shaft -when the knob is turned, butwill not mar the appearance of the device because of its entirely concealed position therein. It will also present a large gripping or contact surface to the shaft.

In radio apparatus especially, my loose bushing will obviate the necessity of carrying dials with different sized holes in stock, for only bushings with different sized holes need be kept on hand with dials having a one-sized hole to receive them. Thus, since different sized holes can be formed in the bushing to accommodate different diameter shafts, it becomes a more economical proposition to carry bushings with different sized holes in stock to fit shafts of diflerent diameters, than to carry different dials with the bushings molded in as at present.

My loose tapered bushing may also be provided with a key to engage the shaft, or it may be made solid, with holes provided to receive balls that engage the shaft. In

any event, my 'method of pulling on the bushing to cause it, or the key, or the balls to close in on the shaft is more advantageous 1924. Serial No. 723,951.

than the set screw or other methods now employed for securing a knob and a dial, cia knob, to an instrument shaft.

In the accompanying drawings, Figure 1 1s a front view of a combined knob and dial embodying my improvements. Figure 2 is a side viewthereof. Figure 3 is a central sectlonal view taken through the same, showing the loose tapered split bushing. Figure 4 is a central sectional view taken through another type of my device. Figure 5 is a central sectional view. taken through a combined knob and dial employing my ball type of loose bushing. Figure 6 is a central sec-- tional view taken through a combined knob and dial employing my loose tapered bushing in conjunction with a Woodrufl' key. And F igure 7 is a central sectional view taken through'a two part knob employing my loose split bushing that is closed in) against the shaft by turning the outer part of the knob when the inner part is held stationary.

Referring to the accompanying drawings for a detailed description of the different forms of embodiment of my invention, the numeral 1 designates a dial, and 2 a knob, for adjusting a spindle or shaft 3 of any type, but more particularly that of a radio instrument. (See Figures 1, 2 and 3.) The extent of this adjustment is determined by a series of graduationsl formed on the outer periphery of the dial. The latter may be made of bakelite, metal, a rubber composition or any other suitable substance, and has an integral hub 01' axial extension 5 in which there is formed a tapering axial hole 6.

The knob 2, which is preferably made of bakelite or the like, is formed with an inner tubular extension 7 having an axial hole 8 which is threaded at its lower end. The tubular extension 7 terminates at its lower end in an annular flange 9 adapted to engage the hub portion 5 of the. dial '1, with its hole 8 in registry with the axial hole 6 in said hub portion of the dial to receive the upper externally threaded end of a loose tubular member such as the bushing 10. The lower part of this bushing is, in this instance, tapering and split to close in against the shaft 3 which it receives, when the knob 2 is turned and the dial is held stationary. Thus, when the knob 2 is rotated, the bushing '10 will have its tapering outer surface drawn against the tapering wall'of the hole 6 in the hub portion 5 of the dial 1, to, contract against the shaft 3 to firmly secure the knob and dial on the shaft without the use of an unsightly and inconvenient set screw.

In Figure 4' I have illustrated a Vernier type knob, through the top of which the hole 8 extends to receive-a vernier shaft 11. The bushing 10 shown in this figure and in Figure 3, has its tapered portion split to enable it to close in readily-against the shaft 3 when the knob is turned, but in the case now to be described the loose bushing may be formed without the slits in its tapered portion.- I

Referring to Figure 5, it will be noted that the loose bushing 10 is not split, but has formed around the lower edge of its taper-v ing portion, a numberzof holes 12 to receive balls 13 of greater diameter than the holes, so that when the knob is turned'as before described, the balls will engage the shaft 3 to firmly secure the dial and knob thereon. In

other words, when the knob 2 is turned, the

tapering portion of the bushing will be drawn against the tapered wall of the hole 6 in the dial 1 to force the balls 13 into clutching engagement with the shaft.

In Figure 6 the tapered loose bushing 10 is not split, but is formed with a lower concave hole to receive a VVoodrufi' key 14 which, when the knob is turned as before, will engage the shaft 3. In other words, when the knob 2 is turned, the tapered portion of the bushing will be drawn against the tapered wall of the hole 6 in the dial, to

force the key 14 into clutching engagement I with the shaft, thereby to hold the knob and dial firmly on the latter.

* In Figure 7 have shown a knob which is made in two parts, the upper part 15 having an inner tubular extension 16 which is internally threaded, and the lower part 17 having a tapering axial hole. Vhen the upper part 15 of the knob is placed upon its lower part 17, as in Figure 7, a loose bushing 18 having its upper end eXternally threaded and its lower end tapering and split, may be forced through the axial hole in the lower part 17 of the knob to receive ashaft 19. The upper knob part 15 may then be screwed on the up-. per threaded portion of the bushing 18, to

draw its tapering portion against the tapered wall of the gxial hole in the lower knob part 17, to cause the split tapering portion of the bushing to firmly clutch the shaft 18 and thereby firmly secure both knob parts upon the shaft. l

Having described my invention, I claim In a device of the type described, the combination with a shaft, of a knob and a dial for conjoint use in turning the shatt, the dial having a tapering axialhole and the knob having a tubular extension adapted to be brought orer'said hole, a loose bushing having a lower tapered, split end adapted to be forced through said hole, and having its upper end threaded for connection with the tubular extension on the knob, whereby, when the knob is turned, the tapered end of the bushing will.be drawn tightly against the 

